Core in a mould ?

Discussion in 'Fiberglass and Composite Boat Building' started by nevilleh, Nov 15, 2010.

  1. nevilleh
    Joined: Sep 2008
    Posts: 73
    Likes: 2, Points: 0, Legacy Rep: 53
    Location: scotland

    nevilleh Junior Member

    Hi,

    Just finally getting underway with our 35' workboat mould.

    Wondering about cores. Most of mine have balsa. Has anyone any thoughts about using nidacore in a hull mould?

    I was wondering about using 3/8" nidacore possibly vaccuum bagged on.

    Hull has quite alot of fairly flat panels.


    Any advice appreciated.


    Neville, Scotland
     
  2. gonzo
    Joined: Aug 2002
    Posts: 15,249
    Likes: 951, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    We are planning on using nidacore on some canoe bottoms. I think that you need to vac it on to get good adhesion and no voids.
     
  3. War Whoop
    Joined: Jun 2003
    Posts: 661
    Likes: 16, Points: 0, Legacy Rep: 84
    Location: Sunny Ft Lauderdale Fla

    War Whoop Senior Member

    Building a Boat in the Mold or the Mold itself?
     
  4. nevilleh
    Joined: Sep 2008
    Posts: 73
    Likes: 2, Points: 0, Legacy Rep: 53
    Location: scotland

    nevilleh Junior Member

    Its for bulding the mould itself. I have used it many times on boats typically on flat panels, but for a mould the panels have a slight bend so the only way I could see would be to use a vacuum bag system.
     
  5. War Whoop
    Joined: Jun 2003
    Posts: 661
    Likes: 16, Points: 0, Legacy Rep: 84
    Location: Sunny Ft Lauderdale Fla

    War Whoop Senior Member

    I bag Sheet core into my Molds.

    Here is the last little bit of 3/4" core going down on a 38' hull mold ,there are perforations
    which allow the excess material out to the surface and maintain a consistent bond line this is bedded in ATC Corebond.

    [​IMG]
     
  6. jim lee
    Joined: Feb 2007
    Posts: 368
    Likes: 20, Points: 18, Legacy Rep: 247
    Location: Anacortes, WA

    jim lee Senior Member

    We infuse our molds with core, glass and most of the framework in one shot. So yeah, core's good.

    -jim lee
     
  7. War Whoop
    Joined: Jun 2003
    Posts: 661
    Likes: 16, Points: 0, Legacy Rep: 84
    Location: Sunny Ft Lauderdale Fla

    War Whoop Senior Member

    That would not work here, I use a lot of piping on the production molds.

    [​IMG]





    And they have to be perfect, This one 38 ' is a inch thick solid glass ,nice pull here.


    [​IMG]
     
  8. jim lee
    Joined: Feb 2007
    Posts: 368
    Likes: 20, Points: 18, Legacy Rep: 247
    Location: Anacortes, WA

    jim lee Senior Member

    Piping's not a problem. You can still add that after the mold is shot. We like infusing 'em 'cause you can build in more overall rigidity in the one shot. By using core and balsa ribbing. Once its shot, we'll add the final framework or what have you.

    Granted our surface quality isn't perfect. But for what we do, its plenty good. What we really want is parts that are dimensionally accurate and infusing them has helped a lot in this respect.

    -jim lee
     
  9. War Whoop
    Joined: Jun 2003
    Posts: 661
    Likes: 16, Points: 0, Legacy Rep: 84
    Location: Sunny Ft Lauderdale Fla

    War Whoop Senior Member

    I could have infused this as I have my own system ,KRYPTON which I have been working on for 20 + years.

    But the all Molds here had to be first rate.

    [​IMG]
     
  10. Herman
    Joined: Oct 2004
    Posts: 1,618
    Likes: 89, Points: 48, Legacy Rep: 1240
    Location: The Netherlands

    Herman Senior Member

    For cores in moulds, Nida would not be my first choice, for the relatively low shear modulus. For approx the same amount of money you have balsa, which gives a stiffer product.

    On the other hand, if it is Nida that you have, go for it. It is not bad, just less "perfect", just "good".
     
  11. Coen
    Joined: Aug 2004
    Posts: 30
    Likes: 1, Points: 0, Legacy Rep: 39
    Location: The Netherlands

    Coen Junior Member

    Herman,
    Why go with a balsa core? In my opinion I would always ago for a non-wood, closed cell core when possible.

    If would look for a PVC or PET foam. I think Airex has both of these types of core.

    Unfortunately, the youngs- and shear modulus will be significantly lower.

    Cheers,

    Coen
     
  12. Herman
    Joined: Oct 2004
    Posts: 1,618
    Likes: 89, Points: 48, Legacy Rep: 1240
    Location: The Netherlands

    Herman Senior Member

    You are right, but not for the same money. Balsa still gives the highest shear modulus for the buck.

    PET (Airex / A3 Composites T90 and T92 foams) is also an option indeed, but I would check where that ends up in the shear modulus / cost ladder.
     
  13. War Whoop
    Joined: Jun 2003
    Posts: 661
    Likes: 16, Points: 0, Legacy Rep: 84
    Location: Sunny Ft Lauderdale Fla

    War Whoop Senior Member

    OK by who's numbers??
     
  14. Herman
    Joined: Oct 2004
    Posts: 1,618
    Likes: 89, Points: 48, Legacy Rep: 1240
    Location: The Netherlands

    Herman Senior Member

    I do not get the question.
     

  15. War Whoop
    Joined: Jun 2003
    Posts: 661
    Likes: 16, Points: 0, Legacy Rep: 84
    Location: Sunny Ft Lauderdale Fla

    War Whoop Senior Member

    You said balsa gives the highest sheer numbers and I asked by who's numbers?
     
Loading...
Similar Threads
  1. dbstormchild
    Replies:
    3
    Views:
    2,359
  2. Highwater
    Replies:
    1
    Views:
    3,181
  3. Midday Gun
    Replies:
    10
    Views:
    209
  4. keith66
    Replies:
    14
    Views:
    465
  5. Doran M. Oster
    Replies:
    27
    Views:
    806
  6. Toepfer Marine
    Replies:
    7
    Views:
    380
  7. Mark C. Schreiter
    Replies:
    12
    Views:
    1,429
  8. Mark C. Schreiter
    Replies:
    33
    Views:
    2,206
  9. fallguy
    Replies:
    7
    Views:
    485
  10. tuna_fan
    Replies:
    5
    Views:
    638
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.